Haenen was recruited from the Mildura Imperials and gave South Melbourne solid service over six seasons. He finished the 1970 Brownlow Medal count as his club's equal third top vote-getter, the same year he made his only finals appearance.
He transferred to Port Melbourne in 1975 and was the ruckman in their 1976 premiership side. In the Grand Final he was reported for assaulting a boundary umpire but was cleared in the tribunal. While he was used a ruckman for most of his time at Port Melbourne, Haenen was primarily a defender during his career, usually at centre half back.
